By about age 50.8 years.
Axial length too short or converging power of the lens/cornea is too weak.
The angle at either end of the eyelid aperture (medial and lateral canthus).
A small fleshy, epidermoid structure attached to the inner portion of the plica semilunaris.
The optic disc is the point of exit for retinal nerve fibers and the entry point for the central retinal artery and vein.
The brain instantly converts it so that it is seen the right way up.
A clear fluid that fills the anterior and posterior chambers of the eye.
Age-related loss in accommodative ability by about 50 years of age.
They secrete oils that help to keep the tear film stable and prevent evaporation of the eye's tear film.
The medial recti bring about convergence of the ocular axes.
The normal optic disc appears as a round or slightly oval structure with a distinct margin.
It produces aqueous humor and contains the ciliary muscle, which controls the shape of the lens.
The lens thickens to increase the refractive power by contraction of the ciliary muscle.
Long-sightedness.
Short-sightedness.
Frontal, Zygomatic, Maxillary.
Roof, Floor, Medial wall, Lateral wall.
The angle formed between the cornea and the iris at the periphery of the anterior chamber.
With convex lenses such as reading glasses, bifocals, or trifocal lenses.
Distant objects are seen clearly, but near vision is blurred.
Convex positive lenses.
Optic nerve head.
Yellow spot.
The pars plana is the flat part of the ciliary body in the eye, located between the iris and the choroid.
Between the cornea and the iris.
The normal optic disc is typically a pinkish-orange color.
Eyelashes help to protect the eye from debris, dust, and other foreign particles.
Via the optic nerve, optic tract, and optic radiations to the visual cortex of the brain.
Cylindrical lenses, hard contact lenses, and astigmatic keratotomy.
Optic nerve, meninges, ophthalmic artery, and sympathetic plexus.
Lacrimal nerve, frontal nerve, trochlear nerve, oculomotor nerve, nasociliary nerve, and abducent nerve.
It influences the refraction of light.
They are openings in the orbit for the passage of nerves and vessels.
Retina
The pars plana is often used as a site for surgical entry into the eye because it is relatively avascular and provides access to the vitreous body and retina.
Eyelashes, meibomian glands, and the openings of the lacrimal ducts.
The opening between the upper and lower eyelids.
The central depression in the optic disc is called the optic cup.
The normal cup-to-disc ratio is usually less than 0.5.
An inverted image.
The structures of the uvea are the iris, ciliary body, and choroid.
The iris is located in the front part of the eye, surrounding the pupil and controlling its size.
The area where the eyeball is penetrated by the optic nerve.
Cornea
Choroid
The pupils constrict to limit the light waves to the thickest central part of the lens.
It plays a crucial role in protecting the eye, maintaining tear film stability, and facilitating the drainage of tears.
They change light impulses into a nerve impulse.
Difficulty in seeing both near and far objects.
The conjunctiva is a thin, transparent tissue that covers the white part of the eye (sclera) and lines the inside of the eyelids.
Concave or negative lenses.
Dura mater, pia mater, and arachnoid.
Blepharitis.
It influences the refraction of light.
Vitreous
The edge of the eyelid where the eyelashes are located and where the eyelid meets the surface of the eye.
A linear decline of 2.3 diopters per decade.
The limbus is the border area between the cornea and the sclera. It is important for surgical procedures and for the drainage of aqueous humor.
Axial length too long or converging power of the lens too strong.
People with myopia can see near objects clearly but distant objects are blurred.
A small difference in the size of the two images.
The mucus helps to trap and remove dust, pathogens, and other particles from the air we breathe.
The ciliary body is located behind the iris and is responsible for the production of aqueous humor and accommodation of the lens.
Optic disc.
Para-nasal sinuses are air-filled spaces located within the bones of the skull and face, connected to the nasal cavity.
To protect the eyes from foreign particles and excessive light, and to help spread tears over the surface of the eye.
The eyelid margin.
A soft, movable fold of the conjunctiva located at the medial canthus of the eye.
Openings of the tear ducts, easily seen on the medial aspect of the upper and lower lid margins when the eyelid is everted.
It influences the refraction of light.
Vitreous humour.
Limbus
A condition where the corneal curvature in one meridian varies from the meridian at 90º, preventing light from coming to a single focus on the retina.
The cornea is located at the front of the eye, covering the iris, pupil, and anterior chamber.
Between the iris and the lens.
They are connected through small openings called ostia.
Contact lenses and refractive surgery.
Retinal arteries and veins.
Anterior ethmoidal nerve and artery, posterior ethmoidal nerve and artery.
Zonules
The frontal, maxillary, ethmoid, and sphenoid bones.
Through a process called fusion.
Contact lenses and surgery.
They secrete an oily substance that prevents the evaporation of the eye's tear film.
At the back of the eyeball and connected to the brain.
To elevate the upper eyelid.
A circular channel in the eye that drains aqueous humor from the anterior chamber into the bloodstream.
They help to lighten the weight of the skull, produce mucus, and contribute to voice resonance.
The orbicularis oculi muscle.
Smooth anterior curvature of the cornea, length of the eyeball, function of the lens, zonules, ciliary muscle, and transparency of the media.
Superior and inferior ophthalmic veins.
The lens, zonules, and ciliary muscle.
Iris
Lens
Fovea centralis.
Infraorbital nerve, artery, vein, and zygomatic nerve.
Sclera
The conjunctiva.
The choroid is the vascular middle coat of the eye, situated between the outer sclera and the inner retina.
Conjunctiva
